From: mike.ab3ap@gmail.com (Mike Markowski)
Subject: [TUHS] The birth of the Z3
Date: Sun, 13 May 2018 17:44:27 -0400 [thread overview]
Message-ID: <86258450-6c66-1a5e-c18c-392f0fd4ec8f@gmail.com> (raw)
In-Reply-To: <20180513213042.0914C18C09C@mercury.lcs.mit.edu>
On 05/13/2018 05:30 PM, Noel Chiappa wrote:
> > From: Clem Cole
>
> > Their is a open question about the need to support self modifying code
> > too. I personally don't think of that as important as the need for
> > conditional instructions which I do think need to be there before you
> > can really call it a computer.
>
> Here's one way to look at it: with conditional branching, one can always
> write a program to _emulate_ a machine with self-modifying code (if that's
> what floats your boat, computing-wise) - because that's exactly what older,
> simple microcoded machines (which don't, of course, have self-modifying code
> - their programs are in ROM) do.
>
> Noel
Rewording that, as I recall from Computability Theory there are three
statements needed for Turing completeness:
1. S <- 0 S is some var
2. S <- S + 1
3. if S=0 goto L L is some line#
Beyond that everything else is icing on the cake. Kind of like needing
nothing more than a bunch of NAND gates to build a computer,
disregarding practicality...
Mike Markowski
next prev parent reply other threads:[~2018-05-13 21:44 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-13 21:30 Noel Chiappa
2018-05-13 21:44 ` Mike Markowski [this message]
2018-05-14 3:27 ` Dave Horsfall
-- strict thread matches above, loose matches on Subject: below --
2018-05-11 22:21 Dave Horsfall
2018-05-12 15:04 ` Clem Cole
2018-05-13 6:52 ` Greg 'groggy' Lehey
2018-05-13 21:07 ` Clem cole
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